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authorTakashi Iwai <tiwai@suse.de>2016-03-01 18:30:18 +0100
committerSasha Levin <sasha.levin@oracle.com>2016-03-09 13:15:23 -0500
commitebe15c00057a4efad2bae1a90b04a20766cefc8c (patch)
tree3835bb522c50d3646ccb991686d401d4167a111b
parent74a8e4d036f86999d15a4f1c24fc6f33423eb338 (diff)
ALSA: seq: oss: Don't drain at closing a client
[ Upstream commit 197b958c1e76a575d77038cc98b4bebc2134279f ] The OSS sequencer client tries to drain the pending events at releasing. Unfortunately, as spotted by syzkaller fuzzer, this may lead to an unkillable process state when the event has been queued at the far future. Since the process being released can't be signaled any longer, it remains and waits for the echo-back event in that far future. Back to history, the draining feature was implemented at the time we misinterpreted POSIX definition for blocking file operation. Actually, such a behavior is superfluous at release, and we should just release the device as is instead of keeping it up forever. This patch just removes the draining call that may block the release for too long time unexpectedly. BugLink: http://lkml.kernel.org/r/CACT4Y+Y4kD-aBGj37rf-xBw9bH3GMU6P+MYg4W1e-s-paVD2pg@mail.gmail.com Reported-by: Dmitry Vyukov <dvyukov@google.com> Cc: <stable@vger.kernel.org> Signed-off-by: Takashi Iwai <tiwai@suse.de> Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
-rw-r--r--sound/core/seq/oss/seq_oss.c2
-rw-r--r--sound/core/seq/oss/seq_oss_device.h1
-rw-r--r--sound/core/seq/oss/seq_oss_init.c16
3 files changed, 0 insertions, 19 deletions
diff --git a/sound/core/seq/oss/seq_oss.c b/sound/core/seq/oss/seq_oss.c
index 72873a46afeb..4b53b8f2330f 100644
--- a/sound/core/seq/oss/seq_oss.c
+++ b/sound/core/seq/oss/seq_oss.c
@@ -148,8 +148,6 @@ odev_release(struct inode *inode, struct file *file)
if ((dp = file->private_data) == NULL)
return 0;
- snd_seq_oss_drain_write(dp);
-
mutex_lock(&register_mutex);
snd_seq_oss_release(dp);
mutex_unlock(&register_mutex);
diff --git a/sound/core/seq/oss/seq_oss_device.h b/sound/core/seq/oss/seq_oss_device.h
index b43924325249..d7b4d016b547 100644
--- a/sound/core/seq/oss/seq_oss_device.h
+++ b/sound/core/seq/oss/seq_oss_device.h
@@ -127,7 +127,6 @@ int snd_seq_oss_write(struct seq_oss_devinfo *dp, const char __user *buf, int co
unsigned int snd_seq_oss_poll(struct seq_oss_devinfo *dp, struct file *file, poll_table * wait);
void snd_seq_oss_reset(struct seq_oss_devinfo *dp);
-void snd_seq_oss_drain_write(struct seq_oss_devinfo *dp);
/* */
void snd_seq_oss_process_queue(struct seq_oss_devinfo *dp, abstime_t time);
diff --git a/sound/core/seq/oss/seq_oss_init.c b/sound/core/seq/oss/seq_oss_init.c
index dad5b1123e46..0b9c18b2e45f 100644
--- a/sound/core/seq/oss/seq_oss_init.c
+++ b/sound/core/seq/oss/seq_oss_init.c
@@ -436,22 +436,6 @@ snd_seq_oss_release(struct seq_oss_devinfo *dp)
/*
- * Wait until the queue is empty (if we don't have nonblock)
- */
-void
-snd_seq_oss_drain_write(struct seq_oss_devinfo *dp)
-{
- if (! dp->timer->running)
- return;
- if (is_write_mode(dp->file_mode) && !is_nonblock_mode(dp->file_mode) &&
- dp->writeq) {
- while (snd_seq_oss_writeq_sync(dp->writeq))
- ;
- }
-}
-
-
-/*
* reset sequencer devices
*/
void